This invention relates to an image forming apparatus using electrophotography, and relates to a developing device and a developer cartridge used in the image forming apparatus.
An image forming apparatus using electrophotography such as a printer, a copier, a facsimile or the like is configured to form a toner image by uniformly charging a surface of a photosensitive body, exposing the charged surface of the photosensitive body to thereby form a latent image, developing the latent image with toner (developer), and transferring the toner image to a recording medium. The toner image is fixed to the recording medium by application of heat and pressure. Residual toner remaining on the surface of the photosensitive body is removed by a cleaning device.
A toner cartridge is mounted (for example, detachably mounted) to a developing device that performs developing. The toner cartridge includes a toner storing portion for storing unused toner which is to be supplied to the developing device and a waste toner storing portion for storing waste toner.
A toner supply opening is formed on the bottom of the toner storing portion for supplying the toner to the developing device. A cylindrical shutter for opening and closing the toner supply opening is provided inside the toner storing portion. A part of the cylindrical shutter protrudes to the outside through an opening formed on a side of the toner storing portion. A rotatable operation lever is provided on the outer part of the cylindrical shutter. By operating the rotatable operation lever, the toner cartridge is locked with respect to the developing device, and, at the same time, the cylindrical shutter is moved to open the toner supply opening. Such a toner cartridge is disclosed by, for example, Japanese Laid-open Patent Publication 2005-227614 (see, Pages 4-5 and FIG. 1).
Here, a seal member is attached to the outer circumferential surface of the cylindrical shutter, in order to seal between the outer circumferential surface of the cylindrical shutter and the inner circumferential surface of the toner storing portion. The seal member is strip-shaped (band-shaped), and an adhesive agent is coated on the backside of the seal member. The seal member is wound around the cylindrical shutter at one revolution in the circumferential direction of the cylindrical shutter. Both end portions of the seal member in the longitudinal direction thereof have inclined end edges which are inclined with respect to the longitudinal direction of the seal member. The seal member is wound around the cylindrical shutter in such a manner that the inclined end edges face each other.